[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Preface Part I. Turbulence: 1. Introduction 2. Coherent structures 3. Proper orthogonal decomposition 4. Galerkin projection Part II. Dynamical Systems: 5. Qualitative theory 6. Symmetry 7. One-dimensional 'turbulence' 8. Randomly perturbed systems Part III. 9. Low-dimensional Models: 10. Behaviour of the models Part IV. Other Applications and Related Work: 11. Some other fluid problems 12. Review: prospects for rigor Bibliography.

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Turbulence, Coherent Structures, Dynamical Systems and Symmetry

The understanding of fluid turbulence has considerably progressed in recent years. The application of the methods of statistical mechanics to the description of the motion of fluid particles, i.e., to the Lagrangian dynamics, has led to a new quantitative theory of intermittency in turbulent transport. The first analytical description of anomalous scaling laws in turbulence has been obtained. The underlying physical mechanism reveals the role of statistical integrals of motion in nonequilibrium systems. For turbulent transport, the statistical conservation laws are hidden in the evolution of groups of fluid particles and arise from the competition between the expansion of a group and the change of its geometry. By breaking the scale-invariance symmetry, the statistically conserved quantities lead to the observed anomalous scaling of transported fields. Lagrangian methods also shed new light on some practical issues, such as mixing and turbulent magnetic dynamo.

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Particles and fields in fluid turbulence

To improve the performance of particle image velocimetry in measuring instantaneous velocity fields, direct cross-correlation of image fields can be used in place of auto-correlation methods of interrogation of double- or multiple-exposure recordings. With improved speed of photographic recording and increased resolution of video array detectors, cross-correlation methods of interrogation of successive single-exposure frames can be used to measure the separation of pairs of particle images between successive frames. By knowing the extent of image shifting used in a multiple-exposure and by a priori knowledge of the mean flow-field, the cross-correlation of different sized interrogation spots with known separation can be optimized in terms of spatial resolution, detection rate, accuracy and reliability.

Theory of cross-correlation analysis of PIV images : Image analysis as measuring technique in flows

https://iopscience.iop.org/article/10.1016/0169-5983(92)90023-P/pdf

New Insights into Large Eddy Simulation

Contents: The State of Turbulence Research.- Contributions of Numerical Simulation Data Bases to the Physics, Modeling, and Measurement of Turbulence.- The Self-Preservation of Turbulent Flows and Its Relation to Initial Conditions and Coherent Structures.- Engineering Turbulence Models.- Chaos and the Onset of Turbulence.- Advances in Turbulence Measurement Techniques.- The Role of Smoke Visualization and Hot-Wire Anemometry in the Study of Transition.- Index.

Advances in turbulence

Cavitation in Fluid Machinery and Hydraulic Structures

Large Eddy Simulation and theoretical investigations of the transient cavitating vortical flow structure around a NACA66 hydrofoil

Copyright Cambridge University Press. Published article may be found at http://journals.cambridge.org/action/displayAbstract?aid=13425.

/pdf/the-proper-orthogonal-decomposition-of-pressure-fluctuations-3qgno6plul.pdf

The proper orthogonal decomposition of pressure fluctuations surrounding a turbulent jet

▪ Abstract Cavitation in vortical structures is a common, albeit complex, problem in engineering applications. Cavitating vortical structures can be found on the blade surfaces, in the clearance passages, and at the hubs of various types of turbomachinery. Cavitating microvortices at the trailing edge of attached sheet cavitation can be highly erosive. Cavitating hub vortices in the draft tubes of hydroturbines can cause major surges and power swings. There is also mounting evidence that vortex cavitation is a dominant factor in the inception process in a broad range of turbulent flows. Most research has focused on the inception process, with limited attention paid to developed vortex cavitation. Wave-like disturbances on the surfaces of vapor cores are an important feature. Vortex core instabilities in microvortices are found to be important factors in the erosion mechanisms associated with sheet/cloud cavitation. Under certain circumstances, intense sound at discrete frequencies can result from a coupli...

Roger E. A. Arndt

Papers

Advances in turbulence

Cavitation in Fluid Machinery and Hydraulic Structures

Large Eddy Simulation and theoretical investigations of the transient cavitating vortical flow structure around a NACA66 hydrofoil

The proper orthogonal decomposition of pressure fluctuations surrounding a turbulent jet

Cavitation in vortical flows